Measurement of the water content of an oil bath



May 12, 1970 M. J. REAY ETAL 3,511,083

MEASUREMENT OF THE WATER CONTENT OF AN OIL BATH Filed July 16, 1968 III@441 ATTJJTK wi zziw ATTORNEYS United States Patent 3,511,083MEASUREMENT OF THE WATER CONTENT OF AN OIL BATH Martyn John Reay,Birmingham, and Norman Frank Smith, Solihull, England, assignors toJoseph Lucas (Industries) Limited, Birmingham, England, a Britishcompany Filed July 16, 1968, Ser. No. 745,178 Int. Cl. C01n 33/28 US.Cl. 73-611 1 Claim ABSTRACT OF THE DISCLOSURE In order to measure thewater content of an oil bath, a chamber is filled with the oil, which isthen heated to a first elevated temperature, excess oil being allowed toescape from the chamber through a valve. The valve is then closed andthe oil is heated to a second higher elevated temperature, the oil thistime being allowed to expand into an expansion pipe the level in whichindicates the water content.

Where an oil bath is used for quenching, it is important that the bathshould be substantially free from water, because the presence of watercan lead to explosions during quenching. This invention relates toapparatus for indicating when the water content of an oil bath exceeds apredetermined acceptable level.

Apparatus according to the invention comprises a chamber, means forsupplying oil from the bath to the chamber, means for heating oil insaid chamber, a valve controlled bleed pipe extending from the top ofthe chamber, an expansion-pipe communicating with the chamber, and meansfor indicating when oil in the expansion-pipe reaches a predeterminedlevel when oil in the chamber is heated with the valve closed.

An example of the invention is illustrated in the accompanying drawing.

Referring to the drawing, oil from an oil bath is conveyed to a chamber11 by way of a pump-motor unit 12, a non-return valve 13 beingincorporated between the pump and the chamber 11, and a valve-controlledoutlet being provided for priming the unit 12.. In the chamber 11 is aheater 14, and extending from the top of the chamber is a bleed pipe 15containing a solenoid-operated valve 16. Extending from inlet of thechamber 11 is an expansion pipe 17 with which are associated a pair ofphoto cells 18, 19 coupled to indicating equipment 20.

In order to ascertain whether the water content of the 3,511,083Patented May 12, 1970 'ice oil bath is above a predetermined safe level,the unit 12 is operated with the valve 16 open until the chamber 11 isfilled with oil. The heater 14 is then operated under the control of afirst thermostat in the chamber 11, so that the oil in the chamber 11 isheated to a predetermined value. At this stage the valve 16 is stillopen and part of the heated oil flows through the valve 16 and the bleedpipe 15. At this stage the chamber 11 is full with oil at apredetermined known temperature. The valve 16 is now closed, and theheater 14 is again operated to raise the temperature of the chamber 11to a second predetermined higher value. The expansion of the oil nowcauses it to rise up the expansion pipe 17, and if the water content isabove the safe value, the photocell 19 is actuated to give a warning.The photocell 18 is positioned so that it will 'be actuated even if nowater is present, so indicating that the apparatus is workingsatisfactorily.

It will be appreciated that the operation of the apparatus is dependenton the fact that the expansion of the oil varies with the water content.It is of course essential to start the expansion from a predeterminedknown temperature, and since the temperature of the bath may vary, thetwo-stage heating arrangement described must be employed so that beforethe oil is allowed to expand into the expansion-pipe the chamber 11contains a known volume of oil at a known temperature.

Having thus described our invention What we claim as new and desire tosecure by Letters Patent is:

1. Apparatus for indicating when the water content of an oil bathreaches a predetermined level, comprising a chamber, means for supplyingoil from the bath to the chamber, means for heating oil in said chamber,a valve controlled bleed pipe extending from the top of the chamber, anexpansion-pipe communicating with the chamber, and means for indicatingwhen oil in the expansion-pipe reaches a predetermined level when oil inthe chamber is heated with the valve closed.

References Cited UNITED STATES PATENTS 2,571,470 10/ 1951 Milligan73-61.l 3,222,928 12/ 1965 Walker 7361.1 X 3,233,448 2/1966 Brown73--61.1

FOREIGN PATENTS 1,122,114 7/ 1968 Great Britain.

S. CLEMENT SWISHER, Primary Examiner J. W. ROSKOS, Assistant Examiner

